ODF (one drop filling) process is a key step during the manufacture of a liquid crystal panel. As shown in FIG. 1, a liquid crystal 2 is dropped onto the TFT substrate 1, a frame sealant 4 is coated onto the colored film substrate 3, and the TFT substrate 1 and the colored film substrate 3 are assembled using a cell assembly process so as to complete the manufacture of the liquid crystal panel. During the manufacture, the primary function of the frame sealant is to bond the TFT substrate 1 and the colored film substrate 3, as well as to seal the liquid crystal within the liquid crystal cell to prevent the contamination of the liquid crystal from the external environment. Here, the frame sealant 4, i.e., an uncured frame sealant 4, has a low viscosity, about 300±50 Pa·s at 25° C., and it appears pasty. After the assembly of the TFT substrate 1 and the colored film substrate 3, it is irradiated by a certain level of UV light and subjected to heating, thereby curing the frame sealant 4, so as to bond the TFT substrate 1 and the colored film substrate 3 together. Now, the frame sealant 4 has a significantly elevated viscosity and appears as a solid. The aforementioned heating process enables further strengthening of the curing level of the frame sealant, thereby enhancing the adhesion of the frame sealant.
Alignment precision is a crucial parameter in the ODF process and is typically measured after UV curing. The so-called alignment precision means the deviation between the alignment markers set at corresponding positions on both the TFT substrate 1 and the colored film substrate 3. Irregular oscillation, the static viscosity of the frame sealant, and the shrinkage of the frame sealant after UV irradiation all affect the alignment precision. With an increasing demands for higher pixels, higher contrast and higher picture quality of the display product, the criteria for the alignment precision has become higher and higher. Too low an alignment precision will cause leakage of light around pixels, thereby reducing the contrast and affecting the picture quality. The existing frame sealants do not have a high static viscosity, with a high shrinkage upon UV curing, causing the issues of poor alignment precision and picture quality.